As is well known, the cost of transporting produce from the fields to the ultimate consumer is in a large degree determined by the gross weight of what is being shipped. Since it costs just as much per pound to transport the cartons in which the produce is shipped as the produce itself, it is desirable that the cartons weigh as little as possible. Thus, although wooden cartons are known, corrugated cardboard cartons are oftentimes utilized for shipping and cold storage of produce because of their low cost and low weight.
As such, although wooden cartons are commonly used, they are costly to manufacture and also substantially increase the cost of shipping due to their weight. In view of these cost considerations, packaging produce in corrugated cardboard cartons has become the preferred mode of transporting fresh produce. Although such corrugated cardboard cartons are thus commonly used because of their lower cost and lower weight, strength is sacrificed. Also, such corrugated cardboard cartons are subject to deterioration due to the effects of moisture thereon. Thus, a serious disadvantage of corrugated cardboard is that it lacks the structural strength of wood.
Additionally, wood produce cartons can not be recycled, whereas corrugated cardboard produce cartons can be recycled into various paper products.
The cost of cold storage and shipping of produce is also partially determined by the amount of floor space taken up thereby. Thus, it is necessary that such cartons be placed in relatively tall stacks to minimize floor space. This, of course, means that the cartons at the bottom of the stacks must be able to support the weight of those cartons stacked above.
Additionally, handling and transporting of the cartons exposes them to various forces which tend to twist or otherwise deform the corrugated cardboard from which they are formed. In particular, when the vehicle transporting the produce turns or sways, the inertia of the cartons causes the stacks to twist and sway. Since the stacks are held stationary only at the bottom, the twisting and swaying motion of the stacks causes a disproportionately large amount of torque to be applied to the walls of the lower cartons.
The produce being transported is frequently wet, and ambient moisture as well the moisture from the produce has a tendency to gradually saturate the corrugated cartons. When this occurs, the load and torque-bearing capacity of the corrugated cardboard cartons greatly diminishes. In this weakened state, the upper corners of the cartons have a tendency to distend outward. This allows the weight of the cartons stacked above to force a higher carton--formerly supported by the corners of a lower carton--to slide into the lower carton and damage the produce contained therein.
The twisting of the stacks may also cause a relatively weak portion of one of the wetted cartons to twist and mishappen, allowing the weight of the carton stacked above to crush the produce contained in the lower carton. In the worst case, the saturated corner of one of the lower cartons could so weaken that it completely buckles, thereby removing one of the corner supports from the stack and potentially causing the entire stack to collapse.
Because of the need to insure adequate ventilation of the produce contained therein and to assure effective control of its environment, i.e., temperature and humidity, prior art corrugated produce cartons are configured such that, when stacked, air channels are formed therebetween and thereinto. The uppermost and lowermost longitudinal corners of the cartons are beveled such that air conduits are formed along the region where four (4) stacked cartons abut. Apertures formed along the bevel of each carton provide air flow from the conduit into each carton.
Such conduits and apertures also facilitate the application of pesticides and the like or inert gases to reduce the likelihood of insect infestation and/or the growth of fungus.
By forming such bevels, the structural strength, i.e., the ability to withstand stacking, of each carton is substantially reduced. This exacerbates the problems associated with wetting of the cartons, thereby further shortening their useful life.
Stacking alignment tabs formed along the upper edge of each end of the carton are received into cutouts formed along the lower edge of each end of the carton to facilitate stacking thereof. During the stacking process, when one carton is placed atop another, the stacking alignment tabs of the lower carton are positioned within the cutout of the upper carton, thereby assuring proper alignment of the cartons in order form a straight vertical stack. This interlocking of adjacent cartons also makes each stack more stable, and thus less likely to topple over.
Although differences exists among different manufactures, such produce cartons are typically approximately 17 inches long, 14 inches wide, and 7 inches high. Also, the exact configuration of the stacking alignment tabs and the cutouts varies somewhat among manufactures.
Maxco, of Reedley, Calif., Weyerhauser, of Bakersfield, Calif., and Georgia Pacific, of Madesa, Calif. all manufacture such produce cartons.
The storage life of fruit stored in such cartons is typically limited not by degradation of the fruit, but rather by the limited storage life of the corrugated cardboard cartons. Degradation of the corrugated cardboard cartons due to moisture prevents such cartons from being used for extended periods of time.
In light of the problems associated with transporting and storing produce in corrugated cartons, it is desirable that the cartons be reinforced in some manner. It is important, however, that the means utilized to reinforce the corrugated cartons not add significantly to the weight, bulk, or cost of the cartons.
It is important that the carton design lend itself to simple and inexpensive mass production techniques. The corrugated portion of the carton should preferably be as simple as possible so that the number of cutting operations necessary to fabricate the cartons is minimized. Likewise, the reinforcing means itself should be inexpensive to manufacture and assemble into the finished carton.
It is also desirable that, in order to minimize inventory, the reinforced corrugated cardboard design incorporate a minimum number of parts, and that these parts be as light and compact as possible for easy handling and storage.
The process of assembling the reinforcing corrugated cartons should be as simple as possible. Every step in the process should be simple enough that it can be performed by machine.
Finally, although the corrugated portion of the reinforced cartons typically will be destroyed by moisture from the produce, it is desirable that the reinforcing means be recyclable, in order that material costs will be minimized.
Necessarily, the recycling process will only be cost effective if used cartons can be simply and easily disassembled. Preferably, the disassembling process should be performable without tools of any kind and without the necessity of undue care being required in order to insure that the reinforcing means is not damaged. Thus, it would be beneficial to provide a simple and effective means of reinforcing corrugated produce cartons so that they, even when wet, will be able to support the weight of the cartons stacked above them, and bear the torque applied upon them due to the twisting and swaying of the stacked cartons.
As such, although the prior art has recognized to a limited extent the problem of increasing the strength of cardboard produce cartons, the proposed solutions to date have been ineffective in providing a satisfactory remedy.